1. Field of the Invention
The present invention relates to a device for damping vibrations at resonance of an emitter by making use of viscoelastic material having the function of dissipating the vibration energy by means of a member which provides a coupling with the emitter.
2. Description of the Prior Art
In the prior art, it was a known practice to damp vibrations of this type by carrying out a treatment which consisted in applying a damping material having viscoelastic properties in free layers which were consequently unstressed. This type of treatment, however, has often proved ineffective.
A device which has been proposed in order to solve this problem makes use of viscoelastic material and is capable of associating this material with the vibration emitter by means of a coupling member which consists of a stressing back-plate having the same nature as the emitter. The back-plate is held in position either by adhesive bonding or by means of an added fastening element such as a screw, ring or the like according to the nature and configuration of the support to be treated.
By way of example, vibration-damping devices of this type find applications in the treatment of train wheels, circular-saw blades, rotating machines, gears, and so on.
In a known device of this type, vibration damping accordingly takes place by shearing of the fibers of viscoelastic material with respect to each other. The viscoelastic material is inserted between the vibration-emitting support and the stressing back-plate which is coupled thereto by any known fastening means. The degree of coupling between the three layers of the composite structure thus formed governs their capacity for responding to the vibration as a separate entity.
In consequence, a certain degree of control of coupling is necessary in order to obtain optimum contact of the viscoelastic material against the emitter, irrespective of the conditions of use.
Coupling control is difficult to achieve and cannot be reliable in known damping devices since they are usually put into operation by hand.
Furthermore, positioning of the different constituent elements of the device is not an easy matter since it is performed in successive steps.
The object of the present invention is to overcome these disadvantages by dispensing with the multiplicity of steps involved in the practical application of the device and with the need to control clamping during the coupling operation.